Quiz 1 Electronic Power Supply Design PDF, Nirma University, September 2024

Nirma University School of Engineering, Institute of Technology Quiz - 1, September - 2024 B.Tech. in Electrical Engineering, Semester - V 3EE302ME24: Electronic Power Supply Design Roll / Supervi...

Nirma University School of Engineering, Institute of Technology Quiz - 1, September - 2024 B.Tech. in Electrical Engineering, Semester - V 3EE302ME24: Electronic Power Supply Design Roll / Supervisor’s initial Exam No. with date Time: 20 Minutes Max. Marks: 20 1. For a series regulator, as the output resistor value approaches zero, the output voltage becomes more and more _______ on load. a. Dependent b. Independent c. None of these d. Insufficient data 2. In linear regulators, the power semiconductor devices are operated in the _______ region. a. Cut off b. Linear c. Saturation d. Reverse breakdown 3. The power dissipated in the series-pass element determines the size of the _______ that needs to be employed. a. Heat sink b. Driver circuit c. Current sensor d. None of these 4. Consider a regulated dc power supply whose instantaneous input voltage is varied from 20 V to 30 V. (approximate input voltage waveform as triangular waveform). Let Output voltage, V0 = 15 V and assume that the output load is constant. Calculate the energy efficiency in this part of power supply due to losses in transistor. Ans: 5. Which of the following layout is preferred? Page 1 of 3  3EE302ME24: EPSD a. (a) b. (b) c. None of these layouts are preferred d. Both can be preferred 6. The zener current is maximum when the load current is ____________. a. Zero b. Infinity c. One d. None of these 7. Why is volt-second balance used? a. To find the inductor current b. To find the capacitor voltage c. To find the capacitor voltage ripple d. To find the inductor current ripple 8. A boost converter that is switching at 50 kHz is supplied with an input voltage that varies between 20 V and 30 V. The output is required to be regulated at 45 V. A load resistor of 5 Ω is connected across the output. If the maximum allowable inductor current ripple is 10% of the load current, estimate the value of the inductance to be used in the boost converter. a. 0.246 mH b. 0.58 mH c. 2.4 mH d. 0.22 mH 9. Which type of switch is used in high frequency applications? a. IGBT b. MOSFET c. TRIAC d. SCR 10. Which type of converter used in mobile charger application. a. Half - bridge converter b. Full - bridge converter c. Fly - back converter d. Cuk converter Page 2 of 3  3EE302ME24: EPSD 11. In a buck converter, what is the rate at which the inductor current ripple rises and falls? a. 1 to 2 % b. 10 - 30 % c. 50-60 % d. 70-80 % 12. Why is isolation needed between the output circuit and the input circuit? a. The primary and secondary winding are having two different grounds. b. The primary and secondary winding are having a common ground. c. There is no ground present in primary and secondary winding. d. None of these 13. A buck–boost converter is supplied with an input voltage that varies between 5 V and 10 V. The output is required to be regulated at 15 V. Find the duty cycle range. a. 0.2 to 0.3 b. 0.75 to 0.6 c. 0.3 to 0.5 d. 0.8 to 0.9 14. A fly-back converter is switched at 50 kHz with a duty cycle of 0.4. It is supplying a 320 W load with load resistor of 5 Ω. The input voltage of the fly-back converter is derived from a 12 V battery. The turns ratio of the converter is. a. 10 b. 3 c. 5 d. 12 15. A boost converter is switching at 10 kHz is to be regulated with maximum output voltage of 30 V connected across 5 Ω load. If the maximum allowable capacitor voltage ripple is 2% of the load voltage and duty cycle is 30 %. Estimate the value of the capacitance to be used in the boost converter. a. 1000 µF b. 300 µF c. 2000 µF d. 100 µF Page 3 of 3